IN-ORBIT CALIBRATION STRATEGIES FOR DRAG-FREE SATELLITES

摘要

In the near future a series of Drag-Free Satellites (DFS) will be launched. This class of scientific satellite missions are basically for research on fundamental physics as well as geodesy. The Drag-Free Attitude Control System (DFACS) is the more complex technology on-board these satellites, with state of the art actuators and sensors specially developed for this purpose, and not yet tested in space. This key technology allows to reduce the residual accelerations on experiments on board the satellites significantly. In order to achieve this very low disturbance environment (for some missions < 10~(-14)g) the Drag-Free Control system has to be optimized. This optimization process is required because of uncertainties in system parameters which demand a robustness of the control system. This paper will present an approach for the in-orbit identification of a drag-free control system. The discussion includes the modeling, with scale factors and cross couplings, possible excitation signals, comparison of different parameter identification/estimation methods as well as simulation results.